ON THE PRESSURE-DEPENDENCE OF THE GRUNEISEN-PARAMETER AND DEBYE TEMPERATURE FOR CSI CRYSTALS

An analysis of the pressure dependence of the Gruneisen parameter gamm a and the Debye temperature theta for CsI based on the model developed by Kumari and Dass is presented. From the pressure dependence of the recoilless fraction behaviour gamma is deduced which shows that gamma varies linearly with pressure as gamma(p, T) = gamma(o) - eta p, where eta is found to be pressure independent. theta(p) also displays a lin ear variation with p, which is consistent with the recoilless fraction behaviour of gamma-ray emission or absorption in the Mossbauer effect for low pressures. Various thermodynamic approximations implied in th e analysis are tested and found to be true.